RRB Junior Engineer / DMS / CMA 2015 · Question 22 of 480

If (x -1) is a factor of 3x3 - 2ox2 - 3x + 6, then a is equal to

Mathematics - Algebra

Aa. 3Correct
Bb. -3
Cc. + 6
Dd. - 6

Answer: A. a. 3

Explanation

Let P(x) = 3x3 -2ax2 - 3x + 6 v x -1 is a factor of P(x) x -1 = 0=> x = 1 P(1) = 0 => 3(1)3 - 2a(1)2 - 3(1) + 6 = 0 => 3-2a-3+6=0 => 2a = 6=>a = 3

Source: Arihant RRB JE Solved Paper 26-Aug-2015 (3rd Shift), Q91–150 — published solved-paper compilation (Q1–90 technical not included in this source) · memory-based

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